The present invention relates to a method for controlling a fuel injection system and an ignition system in an internal combustion engine, and more particularly to a control method for the internal combustion engine of an automotive vehicle which is well suited to meet the driver's various requirements relating to the driving of the vehicle.
Heretofore known electronic fuel injection control systems employ a method of intermittently supplying the fuel in an amount corresponding to the intake air flow rate and also varying the fuel quantity during the period of acceleration and deceleration (refer the below-mentioned (1) and (2)). During constant speed driving, this method can supply the engine with an amount of air and a fuel quantity which are proportional to the load and therefore there is no inconvenience. However, the method is disadvantageous in that the engine cannot be controlled properly during transient conditions, e.g., times of acceleration and deceleration.
As described above, the conventional control systems have been unable to provide satisfactory functions to meet the highly sophisticated and diversified requirements relating to driving performance. On the other hand, while torque servo controls and speed servo controls are proposed (e.g., the below-mentioned techniques (3) and (5)) to meet sophisticated requirements, no satisfactory consideration has been given to an overall control ensuring proper control under all conditions which are encountered by the vehicle.
Note that the prior art techniques relating to these types of systems include the following, for example.
(1) IDEI: "The Engine Controls", Institute of Electrical Engineers of Japan Journal Vol. 101, No. 12, P. 1148 (December 1981) . . . Controls by Microcomputers; This relates to table look-up systems.
(2) NAGAYAMA et al: Centralized Control of Engine by Microcomputers, Systems and Controls, Vol. 24, No. 5, P. 306 (May 1980); This relates to flow charts of engine operations, fuel injection control, ignition timing control and idling speed control.
(3) T. TABE et al: On the Application of Modern Control Theory to Automotive Engine Control, IECOM '85; This relates to torque servos.
(4) JP-A-57-73836
(5) ITO: "Fuel Economy Optimalizing Control System with Compound Control Action on Engine and Transmission", Automotive Engineering, February 83; This relates to speed servos.
The above-mentioned conventional techniques have failed to give due consideration in comprehensively grasping as a system the control of the engine on a vehicle. Thus, there have been a lack of engine control methods which could meet all the situations in which the vehicle is to be used and the difficulty to establish the necessary parameters for such engine control methods has been a disadvantage.
One reason is that the conventional engine control methods are made up of static models despite the fact that the conditions which are encountered by a vehicle are a repetition of steady-state operations, e.g., the constant speed running and idling operation and the transient state operation such as acceleration and deceleration. Moreover, the requirements for the behaviour of the vehicle during the transient conditions have become increasingly severe on the part of the users of the vehicles. As a result, even if measuring devices are installed to observe the transient conditions, their full utilization cannot be ensured by the static model.
In the case of the conventional methods in which the static control model is compensated for the transient conditions, a great deal of manhours are required to materialize and adjust an engine control method for each of different types of vehicles which are diversely different in vehicle characteristics, measuring devices, actuators, etc.